1)
Why does it say "Hen Lo Katzrah"?
1.
Rashi: The reason you were not saved is not due to lack of His hand (ability).
2.
Radak: After teaching them about the good deeds [that they should do] and to veer from the evil deeds, he returns to rebuke them more for their evil deeds. They complain about Kel without reason. They say "we fasted and You did not see" (3). He tells them, He did not see your fast and save you, it is not due to lack of ability to save, or His ear is hard of hearing. He hears your cry, and He has the ability to save you. Your sins caused [that He did not]. They "separate between you and Him" (2), so it is as if He does not hear or have ability to save you.
